How Common Is Dementia?

Although dementia has always been somewhat common, it has become increasingly recognized in recent decades due to improvements in diagnostic techniques. In addition, people have longer life expectancies now, and thus are more likely to develop dementia as a function of older age. About 5% to 8% of adults over age 65 has some form of dementia, and this number doubles every five years after that. It is estimated that as many as half of people in their 80s suffer from some degree of dementia.